1. Field of the Invention
The present invention relates to machining tools, such as circular saws and hollow chisel mortises, having adjustable fences for positioning a workpiece to be machined.
2. Description of the Related Art
A known table saw having an adjustable fence is shown in FIGS. 8 and 9. As shown in these figures, a fence 122 is disposed on an upper surface of table 101 and has a flat plate 123 and an upright guide plate 126, which defines a vertical reference surface 125 for positioning the workpiece. The flat plate 123 has an insertion hole 128 formed in the right side portion as viewed in FIG. 8. A guide slot 130 is formed in the flat plate 123 and has an arc-shaped configuration. A first bolt 145 is inserted into the insertion hole 128 and engages a first threaded hole 147 formed in the table 101, so that the fence 122 can pivot about the first bolt 145. A second bolt 151 is inserted into the guide slot 130 and engages a second threaded hole 161 formed in the table 101, so that the fence 122 can be fixed in position relative to the table 101 by tightening the first bolt 151.
In order to change the pivotal position of the fence 122 to perform a "miter cut" operation, the second bolt 151 is loosened using a tool and the fence 122 is pivoted about the first bolt 145. The movement of the second bolt 151 along the guide slot 130 guides the position of the fence 122. After the desired pivoted position has been reached, the second bolt 151 is tightened to fix the fence 122 in the desired pivoted position.
However, in order to change the position of the fence of the known table device, a special tool such as a box wrench is required. In addition, the operator must operate the tool to engage with and disengage from the bolt. Therefore, the known table devices require troublesome operations for changing or adjusting the position of the fence.